It was $2 to the pound when I was in the US in August 2008, and by January 2009 when I was in Singapore it dropped as low as $1.34=£1 and now its back at $1.65=£1. So its changed quite a lot.
EDIT: You can check on http://www.global-view.com/forex-trading-tools/forex-history/ if you don't believe me.
That website shows that since the end of May, it was still $1.61, just after this, Apple then released the MBPs, it was at $1.61 back in October 2008 too, went to $1.41 then went back up to $1.61 how it HAS been for the past 8months